Yielding ratchet torque wrench



SePL 9; `1947 F. MossBERG 2,427,153

YIELDING RATCHET TORQUE WRENCH Filed May 15, 1945 INVENTOR 05616649' ATTORNEYS Patented Sept. 9, 1947 UNITED Yfs'rrres PATENT OFFICE YIELDING RATCHET .'IORQUE WRENCH .Mossberg, Attleboro, Mass.

Application 'May 15, 19437, .Serial No. 487,146

(Cl.81f52.-'4)

112 Claims "1 This Vinvention relates to an adjustable tension wrench Vfor use Where Yit 'is desired that 4too 'great a strain will not be placed upon the work upon `which the vwrench is used.

Heretofore tension `Wrenches have usually been equipped with some .sort of an indicator which the operator of the wrench must Watch to ascertain the amount of pressure orturning force which "is ,being applied through the lWrench to the work.

` applied so that any excess force will not lbe effective upon the work.

Another :object of `this invention -is to provide `an arrangement so that -t'he amount vof force or turning power applied upon the workmay'be tadjusted forwork of various sizes `or strengths.

Another object vof lthis invention is to `provide a vfriction slip butrto distribute the ffriction which is applied over surfaces .of a large .area `so that the pressure Vper iunit area `will be relatively light and the .surfaces will not dig Iinto yone another or wearexcessively.

With these and other objects in zview, 'the .finvention consists of certain -novel features .of com struction, as will .be more fully described and particularly pointed out in the appended claims.

In the accompanying drawings:

Fig. 1 is a top plan vieWof the wrench;

Fig. 2 isa side elevation 'thereof Fig. 3 is a fragmental viewillustratin'g the top half of thewrench removed and v'illustrating the ratchet .mechanism thereof.;

Fig. 4 is a central sectional .view upon substantially .line 4-'4 of Fig. 1 illustrating the series 'of friction discs in assembled relation about .which this invention Vis centered;

Fig. `5 is a perspective view of one .of these friction discs;

Fig. 6 is a perspective view of la friction disc of the cooperatingset;

Fig. 7 is a frag-mental View similar to Fig. 1

Ashowing a `modell-led marking arrangement.

2 arched Imember which may be adjusted ,to vary 'the pressure upon the disc, indicatingmeans being provided 'to show the amount of pressure which has been applied or the relative value 4of Vturning moment for `the setting of the wrench.

With reference to the drawings Il) designates the member which `either directly .engages .the Work orengagessorne coupling which engages the werkend through which turning moment vis `applied, while Il designates generally Lahandle lever for applying .turningrnoment to themember l0. .The .turningmomentof the member l I is applied to 'themember lill 'through a set of .frictiondiscs .1.2 shown jinFig. 4 with an arrangement 'to conr.trol "they pressure upon thesediscs so that they will slip when .amounts of .turning moment in .excess of .a predetermined l,amount is applied.

'The .member .Hl consists `o1 a .square portion |14 having ailange I5 and an upwardly .extending .square stud lIB with a threaded hole .l1 `for the reception of .a '.bolt Il having .ahead IB.

.The .handle member Il .consists of two .sheet metal .pressed .parts 20m-1d .2l which are .assembled with .their peripheral ,edges in contact so as to leave hollow portions within .for the housing of .actuating mechanism. The two `parts are held .together by rivets .22 with .a spacing collar 23 between the parts. A cylindrical housing .24 is provided with ratchet teeth 25 and is reduced qas at 2.6 at .either-.end .to provide shoulders V2.1, these reduced portions 2.6 extend into .corresponding sized openings in .the .casing Amembers 20 and V2| .to provide a bearing for the .mounting .of the housing .member .24 therein. The housing member .i-s .so mounted as to .be free -to frotatein lthe .handle lever .casi-ng .butisicontrolled by the pawl 2,8 pivoted vas at .2-9 with tivo teeth 30 and 3|. When `the .tooth 3.! fis in engagement with the ratchet teeth 25 movement-.of fthele-ver y-clocllz-wise, `as shown .in Eigfures .e1 .and .3, willicause the housing .member 4.to move with the Vlever lwhile move- .ment `in the opposite `direction -will cause lthe pawl tooth .3| to .ride over "the teeth lfor a -new grip. Conversely when .the .tooth 30 is in engagement with the 4ratchet teeth .25 las .shown in the dotted line .position in Fig. movement in :a counterclockwse .direction of the lever will carry with it the .housing member .24 whiletmovement in Jthe .clockwise .direction willcause this tooth 'to'ratchet .over .the ratchet -teeth' lweithout :exerting any turning movement thereon. The position of the pawl ri213. is {cont-rolled by -a fdog 32 ywhich .has .fa .tail piece .33 in aslot 234 with a spring 35 urging the dog toward the .paw'l where it vmay :engage between vthe 2arms 35, 136 tourge `the "pawl in one fdirectionrorthe'other.about its pivot 29. The dog isshifted .from roneiposition asishown in 'full vlines "i'nFiigJB tto the ldo'ttedline position shown in'Fig.

3 by a slide 31 having a=-1`1nger v:piece 3f8 ventering an opening 39 in the dog and itself slidable in a 3 slot 40 in the casing part 2| by means of the handle portion 42 which extends through the slot and is easily engageable by theoperator.

The housing 24 is provided with a series of notches or recesses 45 hereshown as four in number which receive the projections 46 of a, set of discs 41 having a central hole 49 therein as shown in Fig. 5. Thus these discs are locked to the housing 24 and move with the lever. Another set of discs 49 is provided with one between each of the discs 41. As shown in Fig. 6 each disc 49 has a square hole 50 therein of a size to just receive and fitthe stud I6 of the member I9. Thus, this set of discs 49 is locked to the member I which acts to apply a turning moment to the Work. The discs 49 alternate with the discs 41 and also serve to center the member l0 within the housing 24.

A plate l rests upon the flange I5 of member i9 to support the lowermost of the discs of the sandwiched pile While a sheet metal member 53 has a square hole therein to t the square stud I 6 and surmount the pile of discs. Both of these members turn with the member I9, being secured thereto by means of square openings tting on the square stud I6.

The resilient means for applying pressure upon the discs consists of an arched. plate 54 having a square hole therein to receive the squared portion 55 of the bolt l so that this plate will turn with the bolt. turned down into its threaded socket l1 lmore pressure will be applied by the resilient plate by its being distorted from its arched shape shown. The plate instead of being circular is provided with a series of arms 56, .51, 58 and 59, which may have indicating markings such as 6i) thereon, which arms may be caused to register with a datum line 6I on plate 53 so that some indication of the amount of pressure which is applied by the plate may be observed. For instance, number l may indicate a force applied which would be suitable for tightening a bolt of a quarter inch diameter, number 2 might be the force applied which would be suitable for tightening a bolt for a half inch diameter andl number 3 might be the force which could be withstood by a bolt three-quarters inch in diameter, and number 4 might be the force which would be safely withstood by a bolt 1 inch in diameter. This indicating marking might be otherwise arranged for certain pressures by a scale 63 (see Fig. 7) reading about the periphery of the plate 53 with a datum line on one arm of the arched plate.

One set of discs such as 49 will be made of one material Whereas the other set of discs Will be made of a different material, it being desired that one set of discs will be of softer material than the other so that but one set of discs need be replaced when wear occurs, the softer set of discs taking the Wear. For instance, I might provide one set of discs of hard steel and the other set of discs of chrome plated material. Another variation might be that one set of discs be of metal and the other set of discs be of some plastic material such as Bakelite or some of the other resinous plastics, different combina-- tions being selected to obtain the coecient of friction which is to be had.

It will be readily apparent that being of a friction type control no lubrication would be used between the discs as such lubrication would change the values of the pressures and render the marking inaccurate.

As the bolt 4 From the above it will be readily apparent that I have spread out the surface area over which friction occurs to a large extent by supplying a multiple of discs for the distribution of pres- 5 sure. Thus no one disc or one unit of surface area has any excessive pressure applied upon it. Thus less wear at any unit area will occur and the device will last a longer time.

I claim:

1. In a wrench, a circular head rotatable relative thereto and provided with radially extending teeth, a handle extending radially from said head, a double action ratchet pawl pivoted on said handle for engaging said teeth for urging movement in one or the other selected direction, a work engaging member located Within said head and having an axis concentric with the axis of said head and extending from one side thereof, and a friction clutch Within said head concentric with said head and member and acting between said head and member for transmitting movement of the head to said member until a predetermined force is exerted and to then permit a relative movement between the head and member as said head is turned by the handle a spring coaxial with said head and on the other side thereof, for applying friction to said clutch and means for adjusting the spring for applying a predetermined force.

2. In a wrench, a circular head, a handle radial thereof and rotatable relative thereto, said head being provided with radially extending teeth, a double action ratchet pawl pivoted on said handle for engaging said teeth, a Work engaging member located within said head and having an axis concentric with the axis of said head and extending on one side thereof, and a friction clutch within said head concentric with said head and member and acting between said head and member for transmitting movement of the head to said member until a predetermined force is exerted and to then permit a relative movement between the head and member as said head is turned by the handle, spring means on said work engaging member and on the other side of the head and means to adjust the pressure of said spring on said friction clutch to determine the torque at which relative movement of the head 50 and member will occur.

FRANK MOSSBERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Y Germany 

